The present invention relates to equalizing tank apparatus for volume equalization and air separation of a liquid heat carrier flowing through a circulatory system, especially for a circulatory system for a liquid-cooled internal combustion engine. More particularly, the present invention is directed to an improved tank apparatus of the type including a lower main-flow chamber arranged at the bottom of the tank and provided with a main-flow entrance and main-flow exit connected in series with the coolant circulatory system as well as also a secondary or separation-flow chamber arrangement including a secondary-flow entrance into an upper separation chamber and a secondary-flow exit from the separation chamber for the connection into the main-flow stream. In tank constructions of this type, vent openings are provided between an air chamber space and the top of the separation chamber for accommodating escape of entrapped air in that portion of the flow of coolant through the separation chamber.
U.S. Pat. No. 3,455,377 discloses an equalizing tank of the above-mentioned type. Such equalizing tanks operate such that a portion of the cooling water main flow is discharged as a secondary flow into the separation chamber and is slowed down there in order to accommodate separation of the air particles entrenched in the secondary flow, which air particles then collect in the air chamber of the equalizing tank above the separation chamber. The velocity decrease in a separation chamber is obtained because the flow cross-sections of the secondary-flow entrance and secondary-flow exit are very small in relation to the cross-section of the separation chamber. Since the flow cross-section of the separation chamber, however is usually constructed relatively narrow on account of available space, the secondary flow quantity must be very small in order to maintain the low flow velocity in the separation chamber. However, with such a small secondary flow, the danger exists that with the accumulation of larger air quantities in the main flow, the air particles must pass a number of times through the cooling circuit before they arrive at the separation chamber arranged in the secondary flow.
The present invention contemplates overcoming the above-discussed disadvantages by providing an improved equalizing tank of the type mentioned above in such a way that even with a larger accumulation of air quantities, an effective separation of the air particles is attained.
According to a first important feature of the present invention, a separation chamber arrangement is provided which includes at least two secondary-flow chambers interconnected in series and each having a vent connection discharging into the air chamber of the separation chamber arrangement. The secondary-flow chamber arranged at one end of the series connection is provided with the secondary flow entrance and the secondary flow chamber arranged at the other end of the series connection is provided with the secondary flow exit. The secondary flow chambers connected in series form a multitude of vent places so that the system can be operated with higher flow velocities in the secondary flow, whereby the total cross-section of these secondary flow chambers is constructed so as not to be considerably larger than the cross-section of the corresponding single separation chamber in known equalizing tanks.
A second important feature of the invention which aides in overcoming the above-discussed disadvantages includes the provision of a vent bypass connection leading from the main flow chamber in bypassing relationship to the secondary flow and discharging into the air chamber of the separation chamber arrangement. By this arrangement, a vent place in the main flow chamber is created which is independent of the flow velocities in the secondary flow. This arrangement provides for the separation of air particles which have not entered into the secondary flow and which, in the above-discussed previously known equalizing tanks, are forced to pass through further circulation cycles until diverted into the secondary flow through the separation chamber.
In preferred embodiments of the invention, the opening of the vent bypass connection to the main-flow chamber is arranged geodetically above the opening of the secondary-flow exit discharging into the main flow chamber such that any air particles not separated in the secondary flow and discharging into the main flow chamber can be removed from the main flow chamber via the vent bypass connection.
In order to safely catch the air particles entering the main flow chamber by way of the main flow inlet or entrance, preferred embodiments of the invention provide that the opening of the vent bypass connection into the main flow chamber lies above the flow range between the main flow entrance and the main flow exit.
In order to diminish the danger that the flow in the secondary flow entrance drags along air particles collected in the air chamber, preferred embodiments of the invention provide that the secondary-flow entrance opening into the secondary flow chamber and the opening of the vent connection of this secondary flow chamber which discharges into the air chamber are displaced horizontally with respect to one another.
In preferred embodiments of the invention, a filling connection for the tank is disposed in a range above the chamber wall of the secondary flow chamber provided with the secondary flow entrance, which chamber wall covers the opening of the secondary flow entrance discharging into the secondary flow chamber. In this manner, during filling of the equalizing tank via the filling connection, it is prevented that the rising air from the secondary flow chamber and the liquid particles of the in-flowing liquid flow counter to each other.
In order to accommodate a number of secondary flow chambers within a small space, the present invention contemplates arranging the chambers such that the bulge of one secondary flow chamber reaches underneath an adjacent secondary flow chamber and also forms the secondary flow connection between such chambers.
Although deflections of the secondary flow are themselves favorable for the improvement of the separation process, they nevertheless result in pressure losses. In order to reduce such pressure losses, preferred embodiments of the invention provide that the opening of the secondary flow entrance discharging into the secondary flow chamber is positioned geodetically above the exit for the same secondary flow chamber. For this same purpose, preferred embodiments of the invention provide that the opening of the secondary flow exit from the endmost secondary flow chamber lies geodetically below the opening of the secondary flow connection discharging into this same endmost secondary flow chamber.
In a structurally simple and, therefore, advantageous embodiment of the equalizing tank of the present invention, the secondary flow chamber having the secondary flow entrance is enclosed by an essentially U-shaped partition wall, the wall shanks of which partition wall are disposed at an angle other than 90.degree. in relation to the essentially vertically extending wall web. In this embodiment, the upper wall shank shields the secondary flow entrance against the filling connection whereas the lower wall shank, which continuously ascends from the secondary flow exit to the vent bypass connection, forms the upper closing wall of the main flow chamber. The U-shaped chamber wall preferably consists of a simple separation sheet-iron. This embodiment of the invention preferably also includes an L-shaped partition wall enclosing the side of the secondary flow chamber having the secondary flow entrance which is opposite the U-shaped partition wall. One of the wall shanks of the L-shaped partition wall extends essentially vertically and forms an angle other than 90.degree. in relation to the other wall shank. The wall shank of the L-shaped partition wall which is slanted to the vertical exhibits, in a simple manner, a bulge of the adjacent secondary flow chamber. Also, the L-shaped chamber wall is preferably simple sheet-iron or other metal partition.
A special advantage of the just-described preferred embodiment of the invention resides in that, through the arrangement of only two partition walls in the equalizing tank, a main flow chamber, two secondary flow chambers, a vent bypass connection of the main flow chamber, as well as an upper air chamber are formed.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a single embodiment in accordance with the present invention.